In recent years, nearly all electronic devices have been reduced in size and made lightweight, in particular portable electronic devices such as cellular telephones, two-way radios, laptop computers, personal digital assistants (PDAs), etc. This advancement has been made possible, in part, by the development of new battery chemistries such as nickel-metal hydride, lithium ion, zinc-air, and lithium polymer that enable larger amounts of power to be packaged in a smaller container. These secondary or rechargeable batteries need to be recharged upon depletion of their electrical capacity. This is typically performed by connecting the battery to a battery charger that converts alternating current to a low level direct current of 2-12 volts. The charging cycle typically lasts a minimum of 1-2 hours, and more commonly 4-14 hours. Although the new batteries are a tremendous advancement over the previous generations of batteries, they still suffer from the need for sophisticated charging regimens and the slow charging rates. Some have sought to replace electrolytic batteries with fuel cells. Simply put, fuel cells catalyticly convert a hydrogen molecule to hydrogen ions and electrons, and then extract the electrons through a membrane as electrical power, while oxidizing the hydrogen ions to H2O and extracting the byproduct water. The tremendous advantage of fuel cells is the potential ability to provide significantly larger amounts of power in a small package, as compared to a battery. However, the problem of how to replenish the supply of hydrogen fuel to the spent fuel cell still seeks an elegant and practical solution before widespread consumer acceptance occurs. Some have sought to use methanol as the source of hydrogen, by catalyticly converting or ‘reforming’ the methanol using exotic schemes or in the direct methanol fuel cell. Methanol is more attractive to consumers than gaseous hydrogen, as it is more readily available and can be more easily stored and contained. However, the methanol still needs to be replenished from time to time, and it would be desirable if the user of a small methanol-powered fuel cell could easily and readily determine how much longer the fuel cell will operate until the fuel supply is exhausted. In other words, to measure how much liquid methanol remains in the storage container.